1. Field of the Invention
The present invention relates to a wind turbine blade and a wind turbine generator using the wind turbine blade.
2. Description of the Related Art
The wind turbine blade for a wind turbine generator is desired to be lightweight, highly reliable and easy to manufacture for saving production time thereof. In view of making the wind turbine blade lightweight, the wind turbine blade is configured to have a laminated structure of composite materials. FIG. 1A is a sectional view schematically illustrating a structure of a wind turbine blade. The blade 100 comprises an outer shell 101 having a basic laminated structure, a leading edge reinforcing section 103 having a reinforced laminated structure, a trailing edge reinforcing section 105 (105a, 105b), a upwind-side reinforcing section 104a, a downwind-side reinforcing section 104b and a beam member 102. The leading edge reinforcing section 103, the trailing edge reinforcing section 105, the upwind-side reinforcing section 104a and the downwind-side reinforcing section 104b are arranged respectively in a leading part, a trailing part, a upwind-side part and a downwind-side part of the wind turbine blade 100.
To provide a wind turbine blade reduced in weight and still capable of maintaining the bending rigidity required for the wind turbine blade 100, the blade is constructed such that unidirectional reinforcing material of fiber-reinforced plastic is arranged in a location far from a flexural center X. The unidirectional reinforcing material is also referred to as UD material or 0° material. Thus, often used is the structure wherein UD material is intensively laminated in a center of the upwind-side and the downwind-side (the upwind-side reinforcing section 104a and the downwind-side reinforcing section 104b) and the leading edge part and trailing edge part (the leading edge reinforcing section 103 and the trailing edge reinforcing section 105a, 105b). The outer shell covering the entire surface of the blade 100 can be made of bias materials having plural layers of fiber-reinforced plastic (±45° material or multi-directional material). In the outer shell 101, the part in which UD material is not laminated (the parts other than the leading edge reinforcing section 103, the trailing edge reinforcing section 105a, 105b, the upwind-side reinforcing section 104a and the downwind-side reinforcing section 104b) has a structure such as a sandwich structure wherein, for instance, a core material is interposed between plural layers of bias materials.
FIG. 1B is a pattern diagram illustrating the laminated structure of FIG. 1A in detailed. In FIG. 1B, a solid line indicates a bias material (±45° material) 111, a dotted line indicates UD material (0° material) 112 and a trapezoid (rectangular) indicates a core material 113.
As the outer shell 101, n layers of ±45° material are provided on its outer side and m layers of ±45° material are provided on its inner side. “n” and “m” are both natural numbers. And in each part of the wind turbine blade 100, the following layers are provided between the n layers of ±45° material and them layers of ±45° material. Specifically, p layers of 0° material are provided between the n layers of ±45° material and the m layers of ±45° material in the leading edge reinforcing section 103; q layers of 0° material are provided between the n layers of ±45° material and the m layers of ±45° material in the upwind-side reinforcing section 104a/the downwind-side reinforcing section 104b; r layers of 0° material are provided between the n layers of ±45° material and the m layers of ±45° material in the trailing edge reinforcing section 105a/105b. “p”, “q” and “r” are all natural numbers. In this case, the inequality of q>>q, r exists. For the remaining part, a single layer of core material 13 is provided. Further, the trailing tip (most outer edge) may be covered solely by the outer shell 101 (including the core material 113).
As shown in FIG. 2, 0° material (UD material) is a material whose resin is arranged 0° with respect to a longitudinal direction of the wind turbine blade. In the material, resin is penetrated. The material may be fiber-reinforced plastic whose fibers are laminated 0° with respect the longitudinal direction of the blade. Also shown in FIG. 2 is ±45° material. The ±45° material may be a material whose fibers are laminated one atop another in different directions +45° and −45° with respect to the longitudinal direction of the wind turbine blade. In the material, resin is penetrated. The material may be fiber-reinforced plastic whose fibers are arranged ±45° with respect to the longitudinal direction of the blade. The fiber is, for instance, carbon fiber, glass fiber and so on.
In the case described above, the leading edge reinforcing section 103 has the laminated structure having)(±45°)n/(0°)p/(±45°)m in this order from the outer side to the inner side. The upwind-side reinforcing section 104a and the downwind-side reinforcing section 104b has the laminated structure having (±45°)n/(0°)q/(±45°)m in this order from the outer side to the inner side. The trailing edge reinforcing section 105a/105b has the laminated structure having)(±45°)n/(0°)r/(±45°)m in this order from the outer side to the inner side. The rest has the laminated structure having) (±45°)n/core material/(±45°)m in this order from the outer side to the inner side. “±45°” and “0°” indicate 45° material and 0° material respectively and “n”, “m”, “p” and “r” respective indicate the number of layers.
JP2006-118434A discloses a production method of a lightweight wind turbine blade. The wind turbine blade is used for a vertical axis wind turbine generator. The wind turbine blade is configured such that a first half divided blade and a second half divided blade including wind turbine blade surface layers is laminated and formed by impregnating predetermined fiber material with resin material for lamination mixed with curing agent to form a predetermined space in a wind mill. Next, a blade support layer supporting in a thickness direction in the blade is laminated and formed on circumference surface of an elastic cylindrical member by impregnating a predetermined fiber member with resin material. Then, the cylindrical member is arranged at a predetermined position in a blade longitudinal direction in the blade to press an in-blade support layer against the first half divided blade and the second half divided blade respectively by elastic force in the blade to form the in-blade support layer as one unit with the first half divided blade and the second half divided blade and the first half divided blade and the second half divided blade are coupled and are left as they are for a predetermined period of time. By this, a wind turbine blade is formed by integration of all of the first half divided blade, the second half divided blade and the in-blade support layer by curing action of curing agent.
JP6-66244A discloses a wind turbine blade. The wind turbine blade has a main girder arranged in a longitudinal direction of an outer shell to enhance the strength. In the wind turbine blade, plural layers of unidirectional roving cloth are stacked one atop another along the longitudinal direction of the main girder, and normal glass cloth and a glass mat are stacked over the stack of layers of roving cloth into the shape of a bondage using the tape winding method.